The choice of ultrasonic cleaning machine frequency depends on the cleaning object

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Shanghai Haozhuang Instrument Co., Ltd. has developed the Haozhuang (LNB) ultrasonic cleaning machine, which is energy-saving and environmentally friendly, leading the country. Professional manufacturing is more secure and affordable. 1. Introduction: Ultrasonic waves propagate in the liquid, so that the liquid and the cleaning tank vibrate together at the ultrasonic frequency. The liquid and the cleaning tank vibrate have their own natural frequency. This vibration frequency is the sound wave frequency, so People heard the buzz. With the continuous development of the cleaning industry, more and more industries and enterprises have used ultrasonic cleaning machines. For the principle of the ultrasonic cleaning machine, the high-frequency oscillation signal sent by the ultrasonic generator is converted into high-frequency mechanical oscillation by the transducer and propagated into the medium-the cleaning solvent. The ultrasonic waves are radiated in a dense and dense phase in the cleaning solution. The liquid flows to generate tens of thousands of tiny bubbles with a diameter of 50-500 μm. The tiny bubbles existing in the liquid vibrate under the action of the sound field. These bubbles form and grow in the negative pressure area where the ultrasonic waves propagate longitudinally, while in the positive pressure area, when the sound pressure reaches a certain value, the bubbles increase rapidly and then suddenly close. And when the bubbles are closed, a shock wave is generated, and thousands of atmospheric pressures are generated around them, destroying the insoluble dirt and dispersing them in the cleaning liquid. When the group particles are wrapped in oil and adhere to the surface of the cleaning piece, the oil is emulsified and solid Particles and detachment, so as to achieve the purpose of cleaning parts. In this process known as the "cavitation" effect, the bubble closing can form a high temperature of several hundred baidu and an instantaneous high pressure of more than 1000 atmospheric pressure

2Technical process 1), cleaning before coating The main pollutant before coating is core oil (also called edging oil, core is also called fixed core and core, which refers to the process selected in order to obtain the specified radius and core accuracy ), Fingerprints, dust, etc. Because the coating process has extremely strict requirements on the cleanliness of the lens, the choice of cleaning agent is very important. While considering the cleaning ability of a certain cleaning agent, it is also necessary to consider its corrosiveness and other aspects.
Frequency Ultrasonic cleaning machine working at a very low frequency (in the range of human hearing) will produce noise. When the frequency is lower than 20kHz, the working noise not only becomes very loud, but also may exceed the limits of the safety noise prescribed by the Occupational Safety and Health Act or other regulations. In applications that require high power to remove dirt without considering the damage to the workpiece surface, a lower cleaning frequency in the range of 20kHz to 30kHz is usually selected. The cleaning frequency in this frequency range is often used to clean large and heavy parts or high-density materials.
Low frequencies are often used to clean smaller, more precise parts, or to remove tiny particles. High frequency is also used in applications where the surface of the workpiece is not allowed to be damaged. Using high frequency can improve cleaning performance from several aspects. As the frequency increases, the number of cavitation bubbles increases linearly, resulting in more and denser shock waves that allow them to enter smaller gaps. If the power remains unchanged, the cavitation bubble becomes smaller, and the energy released by it decreases accordingly, which effectively reduces the damage to the workpiece surface. Another advantage of high frequency is that it reduces the cavitation of the viscous boundary layer. Cavitation is the transmission of ultrasonic waves to the liquid with an interactive high-frequency transformation of compressive force and pressure reduction of more than 20,000 times per second. During pressure reduction, the phenomenon of vacuum nuclear cluster bubbles is generated in the liquid. When the compression force is applied, the vacuum nuclear cluster bubbles generate a strong impact force when crushed by pressure, thereby peeling off the dirt on the surface of the object to be cleaned, thereby achieving precision The phenomenon of straight-flow ultrasonic waves flowing in the direction of sound propagation in the liquid for cleaning purposes is called straight-flow. When the intensity of the sound wave is 0.5W / cm2, the naked eye can see the straight flow, and the flow is perpendicular to the vibration surface, and the flow velocity is about 10cm / s. Through this direct flow, the oily dirt on the surface of the object to be cleaned is stirred, and the cleaning liquid on the surface of the dirt also generates convection. Great effect.
Acceleration

The acceleration caused by the pushing of liquid particles. For the ultrasonic cleaner with higher frequency, the cavitation effect is very insignificant. At this time, the cleaning mainly depends on the ultra-precision cleaning of the dirt by the acceleration of the liquid particles under the ultrasonic impact particles.

2) Cleaning and grinding after grinding is an important process that determines its processing efficiency and surface quality (appearance and accuracy) in the production of optical glass. The main pollutants in the grinding process are grinding powder and asphalt, and a few companies will have paint chips during the processing. The types of abrasive powders are different, and they are generally alkali metal oxides based on ceria. According to different lens materials and grinding precision, choose different types of grinding powder. The asphalt used in the grinding process is protective to prevent the polished mirror surface from being scratched or corroded. The cleaning equipment after grinding is roughly divided into two types: one mainly uses organic solvent cleaning agents, and the other mainly uses semi-aqueous cleaning agents.
The cleaning process used for organic solvent cleaning is as follows: organic solvent cleaning agent (ultrasonic wave)-water-based cleaning agent (ultrasonic wave)-municipal water rinse-pure water rinse-IPA (isopropanol) dehydration-IPA slow pull drying. The main purpose of organic solvent cleaning agent is to clean asphalt and paint chips. The previous solvent cleaning agents mostly used trichloroethane or trichloroethylene. Trichloroethane is an ODS (Ozone Depleting Substance) product, which is in the phase of obsolescence; long-term use of trichloroethylene is prone to cause occupational diseases, and because trichloroethylene is very unstable, easily hydrolyzed and acidic, it will corrode lenses and equipment. To this end, domestic cleaning agent manufacturers have developed and produced non-ODS solvent-based cleaning agents, which can be used to clean optical glass; and this series of products have different physical and chemical indicators, which can effectively meet the requirements of different equipment and process conditions. For example, in the production process of a few companies, there is a layer of lacquer on the lens surface that is difficult to handle, requiring the use of organic solvents with special solubility; the solvent cleaning tank condenser tube of some companies' cleaning equipment is mainly used for less water-based cleaning agent It is cleaning abrasive powder. Since the grinding powder is an alkali metal oxide, the cleaning ability of the solvent is very weak, so the grinding powder generated in the lens processing process is basically removed in the water-based cleaning unit, so it puts extremely high requirements on the water-based cleaning agent . Previously, due to the limited variety of water-based cleaning agents for optical glass in China, many foreign-funded enterprises used imported cleaning agents. And domestic companies have developed optical glass cleaning agents and successfully applied them to several large optical glass production plants in China. The cleaning effect can completely replace imported products, and it is superior to imported products in indicators such as corrosion (corrosion resistance). The cleaning process used for semi-aqueous cleaning is as follows:
Semi-aqueous cleaning agent (ultrasonic)-City water rinsing-Water based cleaning agent-City water rinsing-Pure water rinsing-IPA dehydration-IPA slow drawing drying The biggest difference between this cleaning process and solvent cleaning is that the first two One cleaning unit: organic solvent cleaning only has good cleaning effect on asphalt or paint chips, but it cannot clean inorganic materials such as grinding powder; semi-aqueous cleaning agents are different, not only can clean asphalt and other organic pollutants, but also grinding powder The inorganic substances have good cleaning effect, which greatly reduces the cleaning pressure of the water-based cleaning agent in the subsequent cleaning unit. The characteristic of semi-aqueous cleaning agent is that the evaporation rate is very slow and the smell is small. The equipment cleaned by semi-aqueous cleaning agent does not need to seal the condensation and distillation recovery device in the first cleaning unit. However, due to the high viscosity of the semi-aqueous cleaning agent, there are not many domestic companies that apply this process. One of the reasons is that the semi-aqueous cleaning agent is mostly imported from the water-based cleaning unit. The semi-aqueous cleaning process is basically the same as the solvent cleaning process. . Solvent cleaning is a relatively traditional method. Its advantages are fast cleaning speed and high efficiency. The solvent itself can be continuously distilled and recycled for recycling; but the disadvantages are also obvious. Because the production environment of optical glass requires constant temperature and humidity, all are closed workshops. The smell of the solvent will have some impact on the working environment, especially when using semi-automatic cleaning equipment that is not closed. It is improved on the basis of traditional solvent cleaning. It effectively avoids some weak points of the solvent, can be non-toxic, has a slight odor, and the waste liquid can be discharged into the sewage treatment system; there are fewer supporting devices on the equipment; the service life is longer than the solvent;

Shanghai Haozhuang Instrument Co., Ltd. is a technologically innovative high-tech enterprise based in Shanghai and radiating the whole country. The company has first-class technical staff and a good team of technicians, with advanced technology and strong development strength. The company gathers high-tech experimental instruments R & D, production and sales in one, its products have eight series and more than 100 varieties. Relying on modern science and technology, the company continuously improves product quality and launches new products to keep it up to the international level. The products are exported to all parts of the country, and have won the trust of users with excellent quality and perfect service.

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